Method of processing a ceramic electrolyte, and related articles

A method for processing a ceramic electrolyte suitable for use in a fuel cell, the method comprising the steps of:

• situating a ceramic electrolyte layer over an anode layer, wherein the electrolyte layer comprises a top surface, a bottom surface, and a number of microcracks extending at least partially between the two surfaces, such that the bottom surface of the electrolyte layer is adjacent to the anode layer;
• pretreating the ceramic electrolyte layer prior to operation of the fuel cell, by subjecting the ceramic electrolyte layer to a stress sufficient to initiate microcracks in the electrolyte layer, by:
• exposing the top surface of the electrolyte layer to an oxidizing atmosphere, and the bottom surface of the electrolyte layer to a reducing atmosphere;
• and
• heating the electrolyte layer, wherein the stress causes a substantial increase in the number of microcracks, or in the size of the microcracks, or in both the number of the microcracks and their size;
• infiltrating the pre-treated ceramic electrolyte layer with a liquid precursor comprising at least one oxidizable metal ion, so as to obtain an infiltrated ceramic electrolyte layer;
• and
• heating the infiltrated ceramic electrolyte layer to a temperature sufficient to convert at least some of the metal ions to an oxide, thereby, significantly reducing the average size of a selected number of microcracks.

A solid oxide fuel cell comprising:

• an anode, a cathode, and a ceramic electrolyte disposed between the anode and the cathode, wherein the ceramic electrolyte is formed by a method comprising:
• situating a ceramic electrolyte layer over an anode layer, wherein the electrolyte layer comprises a top surface, a bottom surface, and a number of microcracks extending at least partially between the two surfaces, such that the bottom surface of the electrolyte layer is adjacent to the anode layer;
• pre-treating the ceramic electrolyte layer prior to operation of the fuel cell, by
• subjecting the ceramic electrolyte layer to a stress sufficient to initiate microcracks in the electrolyte layer,
• by:
• exposing the top surface of the ceramic electrolyte layer to an oxidizing atmosphere and the bottom surface of the electrolyte layer to a reducing atmosphere;
• heating the ceramic electrolyte layer, wherein the stress causes a substantial increase in the number of microcracks, or in the average size of the microcracks, or in both the number of the microcracks and their average size;
• infiltrating the ceramic electrolyte layer with a liquid precursor comprising at least one oxidizable metal ion, so as to obtain an infiltrated ceramic electrolyte layer;
• and
• heating the infiltrated ceramic electrolyte layer to a temperature sufficient to convert at least some of the metal ions to metal oxides, thereby significantly reducing the average size of a selected number of microcracks.